Are you feeling a need to calm down, and feel centered. The calming breathing is a simple breathing technique that can be done very comfortable from almost anywhere.
To do this find a comfortable seat. You can sit in a more traditional manner on a meditation cushion on the floor. You can also do this from a seat just be sure to keep a tall spine.
Once you find you seated position, take your hands on your knees and join the thumbs and the index finger together. Then with the other fingers open and the hands facing up you are doing a mudhra called Jñana Mudhra
Then take a breath to start. centering yourself. Close the eyes.
You will breath in through the nose and out through the nose. after every inhale you will hold the breath. Do this with a ration of 4-2-4 to start. That is, take and inhale for a count of 4, the hold the breath for 2, then another exhale to a count of 4. Repeat this process for 5 min to start. Eventually you can do this for an hour and you will feel very relaxed.
I have a quick video you can watch and practice with me to start. Then try on your own